- Add sortable.js tests (12 tests): drag/drop, reorder, early returns, edge cases
- Use target.before()/after() instead of list.insertBefore() in sortable.js
- Extract hydrateEventFromRequest() to eliminate duplicated code in createEvent/editEvent
- Disable SonarQube rule php:S1448 (too many methods per class)
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>